Controlled trial of propranolol in hypertension.

A trial of oral propranolol as a hypotensive agent was designed to provide adequate treatment periods. Twenty-eight patients with essential hypertension, with a mean blood pressure of 190/111 mm. Hg, were controlled on 120-320 mg. of propranolol daily. Their mean treated blood pressure was 153/91. They then entered, on a randomized and double-blind basis, a cross-over trial of two 16-week periods, blood pressure being measured fortnightly. Propranolol caused a statistically significant fall in blood pressure when compared with placebo. When propranolol was withdrawn blood pressures rapidly rose to hypertensive levels, though not to untreated levels. No postural hypotension was found, but a small change in blood pressure levels on exercise was noted.